Energy supply vehicles and industrial trucks as well as methods for operating energy supply vehicles are known in basic principle. Thus, for example, EP 2 538 518 A1 discloses a rapid charging device and a mobile charging device. The rapid charging device is mounted on a vehicle, so that a mobile charging device is formed. The rapid charging device comprises a plurality of energy storage units, which can be connected to an electrically drivable vehicle via an electrical circuit and a detachable electrical plug connector in order to charge its electrical energy storage unit. US 2012/0212174 A1 and US 2012/0299531 A1 also disclose vehicles of this kind.
Even though the prior art has proven itself, drawbacks are nonetheless found, in particular when the electrically drivable motor vehicle is constituted by an industrial truck. Industrial trucks with an electric drive unit obtain the electrical energy required for their intended driving operation from an energy storage unit that is contained in the industrial truck. The electrical energy storage unit is typically designed as a rechargeable battery. In the prior art, usually a lead acid battery, which supplies a battery voltage of about 24 V to about 80 V and an electrical capacitance of about several hundred ampere hours (Ah), is provided for such a rechargeable battery. Industrial trucks of this kind are employed, for example, as pallet trucks, forklift trucks, traction vehicles, or the like. They are generally driven by a driver; that is, the control of the industrial truck is in the hands of a driver on board the industrial truck.
In recent times, besides driver-operated industrial trucks, also self-driving or remotely controlled industrial trucks have been employed. Preferably, what is involved here are autonomously navigating industrial trucks, which independently transport goods from a given pickup site to a given target site. Trailers, which are correspondingly pulled by the industrial truck, may come into question here as well. Furthermore, the industrial trucks can also be remotely controlled, at least in part.
Because of the properties of lead acid rechargeable batteries that are usually used in industrial trucks, in particular as electrical energy storage units, the charging of the rechargeable batteries generally occurs externally to the respective industrial trucks due to the high capacity of the energy storage units. This means that the respective rechargeable battery is uninstalled from the respective industrial truck and connected to an appropriate charging station. The charging station charges the rechargeable battery over several hours. In the case of smaller industrial trucks, it can also be provided that the industrial truck is parked at the charging station for the duration of the charging operation. Fundamentally, however, a great expenditure of time is required in order to charge the rechargeable battery of the industrial truck. This applies fundamentally, of course, for other kinds of vehicles as well.
Particularly in the case autonomously driving industrial trucks, but also in the case of remotely controlled industrial trucks, it is not generally provided that the rechargeable battery is uninstalled or exchanged for the purpose of charging, but rather the industrial trucks are taken out of intended transport operation in order to charge the rechargeable battery or else charged repeatedly by way of inductive charging areas during the intended operation. For this purpose, a corresponding complicated and cost-intensive infrastructure is required in terms of building structure, the consequence of which is, moreover, an inability to use the autonomously controlled industrial truck in a flexible manner.
Furthermore, because the charging of the rechargeable batteries is carried out by means of a charging device connected to a public energy supply grid, the charging power is limited to the power that is available at the respective terminal of the public energy supply grid. The rechargeable battery can be charged, for this very reason, only with a limited power. Furthermore, the charging device would also need to have a correspondingly high-power design in order to be able to supply a suitably high charging power.